Canadarm2, the ISS robotic arm built by the Canadian space agency
ESA / NASA
The most precise clock of the space is launching in a few days and will begin to build a highly synchronized network from the best clocks on the earth. But the project, decades of preparation, will only work a few years before it burn While the International Space Station is at the end of the decade.
The atomic clock set in space (ACES) is a mission of the European Space Agency (ESA) which will generate a temporal signal with unprecedented precision, then will transmit it via the laser to nine stations on the ground because it passes over 27,000 kilometers per hour. This network of clocks will be in extremely narrow synchronization and will provide a very precise stopwatch in the world.
The result is that the aces will be able to test Einstein's general theory of general relativityWho says that the time passing is affected by the force of gravity, with great precision. It will also help research everything, from dark matter to string theory.
Aces should be launched on April 21 aboard a Spacex Falcon 9 Rocket of Kennedy Space Center, Florida. Once at the ISS, the robotic arm of the Canadian space agency – Canadarm2 – will attach it outside the ESA Columbus laboratory, where it will remain in the space of space.
The package actually includes two clocks: one called SHM has the ability to remain stable for short periods, which will allow it to help calibrate the other, called Pharao. Together, these clocks will be so precise that they will lose less than a second out of 300 million years – 10 times more precise than clocks on board GPS satellites.
Pharao is fundamentally shaped on an atomic clock in Paris which occupies an entire room. Miniaturize this technology in something that takes less than a cubic meter and can also survive the rigors of a launch of rocket and a life in space, was not an easy task.
To generate a precise clock signal, the pharao spits a fountain of cesium atoms cooled to an almost absolute zero and observes their interaction with the microwave fields. On Earth, this requires a device up to 3 meters high, but in microgravity, these atoms can be sprayed in a slower and smaller fountain, which allows it to be much smaller.
Simon Weinberg AT ESA says that the device is so sensitive that the simple fact of putting a teaspoon nearby could create an electromagnetic field strong enough to destroy the clock. “Just to say it in context, it is better than a thousand million millions of seconds that we are trying to measure here,” says Weinberg. “It is therefore a hell of difficult work.”
The concept for Aces dates back to the 1990s and was originally planned for the launch on the space shuttle, which retired in 2011. Once it will arrive in space, the first signal will not arrive at a land clock for a year and a half – it will take about six months to order it, then a year of measure will be necessary to isolate the noise and delete the signal of the clock.
After that, the ACEs will operate until 2030, after which the ISS will be deliberately crushed in the atmosphere of the earth and burned. At this stage, new super-preccimate watches called optical clocks are likely to have made atomic clocks, except obsolete on earth, although they are not sufficiently small or robust for use in space at that time.
Weinberg says that at one point, ESA will seek to launch a new generation of AS to replace what is lost on the ISS, regardless of the most appropriate technology at the time. “We would be far from that, and we had to bring together support and funding and so on to make sure that this happened.”
